CSIR Climate modellers take on enormous task of modelling the future of climate change through an African lens

The Council for Scientific and Industrial Research (CSIR) is developing Africa’s first Earth System Model that would make an input into the sixth Assessment Report (AR6) of the Intergovernmental Panel on Climate Change (IPCC).

A total of 30 global climate models exist, with only the Australian model having its genesis in the Southern Hemisphere. CSIR climate modellers have taken up the task of developing the first African-based Earth System Model. This will be a coupled model that will incorporate the physics and chemistry of the atmosphere and the oceans. It aims to answer questions such as what might happen to Africa’s climate if greenhouse gas concentrations continue increasing, and whether climate change will result in the more frequent occurrence of strong El Niño events and drought in the Southern African region.

“This will be the only model developed through an African lens,” explains CSIR climate modeller, Prof Francois Engelbrecht, who is leading the development of the coupled model. The African-based Earth System Model will have a special focus on improving the way thunderstorms and rainfalls over Africa are simulated. It will also focus on the Southern Ocean and the African savanna as they play a big role in African climate dynamics.

Last year, the CSIR officially became a Coupled Model Intercomparison Project Phase 6 (CMIP6) registered group of the World Climate Research Programme. CMIP6 is an experimental design for a framework for global climate change modelling until 2020. The CSIR also boasts being the first CMIP registered group in Africa meaning that the AR6 will, for the first time, contain African-derived projections of future global climate change.

In AR4 and AR5 of the IPCC, Africa was the only continent for which climate models have not improved – a clear sign that none of the existing models has been developed through an African lens. The IPCC’s assessment reports are the single most important summary of climate change knowledge globally and up to now. The reports assess the evidence of climate change that has occurred to date, combines climate change projections obtained from all leading climate change institutions globally and converts the information collected into a set of plausible climate futures.

Why is the CSIR zooming into global climate models?

The current global models display data at a resolution of 50 – 200 km, which is inadequate to allow for the understanding of the fine scale dynamics. “This new model will include processes at a resolution of 1 – 10km, which we think will enhance the climate sensitivity of the model in respect of the ocean and land in the Southern Hemisphere,” said CSIR Oceanographer, Dr Pedro Monteiro, who leads the development of the oceanic components of the model. This will also make the decadal and centenary projections more accurate. “It will allow us to model processes that respond quickly to change, similar to monitoring a patient’s breathing and heart beat,” explains Monteiro. This “observing” of the Southern Ocean is also supported by the CSIR’s climate change ocean robotics platform.

South Africans have already had a taste of the harsh conditions under climate change this past summer. “Climate change is already with us and the development of this model will result in improved and reliable projections of the changes in climate over Africa in coming decades,” says Engelbrecht. The coupled model and its component models are already in use at the CSIR and will increasingly be used to inform climate change impact studies. The model projections will be made available publically to a number of sectors to better plan for climate change.

The CSIR’s investment in the development of this model is aimed at informing the country’s adaptation strategies for climate change, which directly supports the Department of Environmental Affairs and national development plans. Projections generated by the CSIR have directly informed the Intended Nationally Determined Contribution on Adaptation that South Africa has submitted to the United Nations Framework Convention on Climate Change. The model projections are also informing South Africa’s national communication on climate change.

The amount of computing power required to enable CSIR climate modellers to participate in CMIP6 is considerable, amounting to tens of millions of central processing units per hour. This computing power is provided by the CSIR’s Centre for High Performance Computing. The successful development in building the first African-based Earth System Model will position the CSIR as a modelling hub in Africa.